How to properly assign spatial reference to converted AutoCAD data?

Question

I know this is a frequent problem, I myself confronted with this problem many times, yet somehow each Autocad dataset I received is different (although they're from the same area). To some data, the projection I gave them worked perfectly, and in this case it didn't.

So, I've recently received some AutoCad data. Converted them in ArcMap. They are missing spatial reference. But I know their location. They're suppose to be in a specific city in Romania.

So first thing I did, I gave them the Stereo 70 projection (Romania's national projection), I assumed this is the projection they were created in, the data gets somewhere in the middle of the Mediterranean Sea. Second thing I tried is is giving them WGS84, and they got somewhere in the Atlantic Ocean ;)

PS: I use ArcGIS 10.1

PS2: I've tried all 3 conversion methods (I know) in ArcMap.

PS3: The autocad data came with no spatial reference. I only know they should be in a specific city.

Answer 1

As you have mentioned in the comments, your old and new CAD files do not overlap, when imported in ArcGIS. This means, that they do not have a consistent coordinate system.

You could either correct them in AutoCAD, which is a better option, since their topology will be maintained, or you could import them into a geodatabase, and then use Spatial Adjustment to align the old data with the new data.